Two different (acetylacetonato)(bipyridine)copper(II) complexes in one single crystal: [Cu(acac)(bipy)(N₃)] and [Cu(acac)(bipy)(H₂O)]ClO₄

The reaction of copper(II) perchlorate with lithium acetylacetonate and 2,2′-bipyridine, in a 1:1:1 molar ratio, gives the mixed-ligand complex [Cu(acac)(bipy)(H₂O)]ClO₄, 1. The reaction of 1 with NaN₃ leads to a complex with the formula [Cu(acac)(bipy)(N₃)][Cu(acac)(bipy)(H₂O)]ClO₄, 2. The crystal structure of 2 has been solved: it crystallizes in the triclinic system, space group P-1, Z = 2, a = 11.1171(5) Å, b = 11.9925(6) Å, c = 15.2336(5) Å, α = 92.885(2)°, β = 108.344(2)°, γ = 115.838(2)°. The structure of 2 consists of mononuclear [Cu(acac)(bipy)(N₃)] entities, cationic [Cu(acac)(bipy)(H₂O)]⁺ species and ClO^- ₄ as counterion. In both complexes the copper(II) ions exhibit a square-pyramidal stereochemistry with two nitrogen atoms of 2,2′-bipyridine and two oxygen atoms of the acetylacetonato ligand in the basal plane, the apical positions being occupied by the aqua and, respectively, the azido ligands.